Deflector for abrasive-accelerator in blasting machine

ABSTRACT

In a deflector for an abrasive-accelerator in a blasting machine, comprising a hollow tubular body having at one end a central opening for receiving an impeller of the accelerator, with the other end being detachably attached to a chute section of the accelerator, and a slot formed locally through the circumferential wall of the body for hurling particles of abrasive therethrough towards the rotating vanes surrounding the rotating impeller, the slot having a parallelogram configuration and being inclined relative to the central longitudinal axis of the deflector body, said inclined slot being of a circumferential width such that the angle formed by the radial outermost end edges of the parallelogram relative to the longitudinal central axis of the body corresponds to the angle through which the particles are blasted by the vanes onto the surface of a workpiece and that the overall axial length of this parallelogram is not greater than the breadth of the vane. Such a deflector is able to blast abrasive particles with uniform density onto the work surface and can increase the effective working length of blasted particles received by the surface and also can reduce the time required for the processing of the surface.

United States Patent 191 Maeda 1 Oct. 15, 1974 1 DEFLECTOR FOR.

ABRASlVE-ACCELERATOR IN BLASTING MACHINE [76] Inventor: Riichi Maeda,14-9, Higashi Tateishi 3-chome, Tokyo, Japan [22] Filed: June 27, 1972[21] Appl. No.: 266,731

[30] Foreign Application Priority Data Primary ExaminerDonald G. KellyAttorney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT In adeflector for an abrasive-accelerator in a blasting machine, comprisinga hollow tubular body having at one end a central opening for receivingan impeller of the accelerator, with the other end being detachablyattached to a chute section of the accelerator, and a slot formedlocally through the circumferential wall of the body for hurlingparticles of abrasive therethrough towards the rotating vanessurrounding the rotating impeller, the slot having a parallelogramconfiguration and being inclined relative to the central longitudinalaxis of the deflector body, said inclined slot being of acircumferential width such that the angle formed by the radial outermostend edges of the parallelogram relative to the longitudinal central axisof the body corresponds to the angle through which the particles areblasted by the vanes onto the surface of a workpiece and that theoverall axial length of this parallelogram is not greater than thebreadth of the vane. Such a deflector is able to blast abrasiveparticles with uniform density onto the work surface and can increasethe effective working length of blasted particles re ceived by thesurface and also can reduce the time required for the processing of thesurface.

1 Claim, 8 Drawing Figures mammal 1 51914 SHEET 101- 2 FIG! AIENTEB UN 151874 sum 2 or 2 FIG. 6 I

PRIOR ART PRIOR ART T R A R m R P DEFLECTOR FOR ABRASIVE-ACCELERATOR INBLASTING MACHINE BACKGROUND OF THE INVENTION 1. Field of the InventionThe present invention is concerned with a deflector for anabrasive-accelerator in a blasting machine, and more particularly itpertains to an improvement in such a deflector.

2. Description of the Prior Art A known abrasive particles acceleratorcomprises, as shown in FIGS. 6 and 7, a base frame 1, casing 2 fixed tohis base frame 1, a chute 3, a deflector 4 attached to said chute 3, anda disk 5 provided concentrically with said deflector 4. The disk 5 isrotated via a pulley 8 and a shaft 9. On one flat surface of this disk 5are attached a plurality of vanes 6 radially of the disk. In the centralopening of the disk 5 is positioned an impeller 7 which is fixed to theshaft 9. A slot is formed locally through the circumferential wall ofthe deflector 4 so as to face the vane 6 so that particles of abrasivemay be hurled therethrough toward the surfaces of the vanes 6. The slot10 is eigher square or rectangular in configuration when viewed fromdirectly thereabove as shown in FIG. 8 so that its opposing two edges10a and 10a are parallel with the central longitudinal axis C or withthe central rotating axis of the impeller and the vanes, and also thatthe opposing other two edges 10b and 10 b of this slot 10 areperpendicular to said central longitudinal axis or to said opposing twoedges l0a.and 10a and are parallel relative to each other. The length aof each edge 10a of one pair is not greater than the breadth W of thevane 6. The length b of each edge 10b of the other pair is equal to theare formed on the circumferential wall of the deflector with an angle orextending from the center of a circle and corresponding substantially tothe angle [3 through which particles of abrasive are blasted by thevanes 6. The particles of abrasive which are discharged through the slot10 are then blasted onto the surface of the workpiece 11 through ablasting angle B which is substantially equal to said center angle a, sothat the surface of the workpiece 11 is processed through the range ofarea defined by the breadth d and the length L as shown in'the drawmg.

As indicated by the broken lines in FIG. 7, the density of the particlesof abrasive at the surface of the workpiece 11 is such that the profileof the density of the blasted particles of abrasive takes a sort ofangular configuration, in which this angular profile for the entirelength L of blast shows a progressive downward inclination on both sidesof this angular profile. As will be understood from the drawing, thelength L covered by those blasted particles located in that portionhaving a density sufficient for being useful in processing said surfaceof the workpiece is seen to be considerably small as compared with theoverall length L of the blasted particles. Accordingly, the amount ofthe abrasive particles serves to be quite critical in processing so thatin case the amount discharged is smaller than the optimum rate of blast,the length L of the useful particles of blast will become very small.Contrariwise, in the event that the rate of blast is greater than theoptimum rate, the length L will become closer to the length L, but thenumerous streams m of the bouncing particles which occur after they runinto the surface of the workpiece as they are blasted from the vaneswill obstruct the paths of the particles being blasted from the vanesand thus they interfere with these fresh particles coming from thevanes, causing uneveness in the processing of the surface. In order tosolve these problems, it is considered that the area of opening of thehurling slot may be reduced. However, in view of the fact, as statedabove, that the length b of the opposing edges of the slot governs theangle B of the blast of the accelerator, it is impossible to reduce thislength. On the other hand, the length a of the opposing other edges ofthe slot is determined as a matter of course relative to the breadth Wof the vane in view of the wear of the vane. If this length a is reducedbeyond the optimum length, the vane will locally become worn outquickly.

SUMMARY OF THE INVENTION It is, threfore, the primary object of thepresent invention to provide a deflector having a slot of an im' provedconfiguration for hurling particles therethrough to make it possiblethat, irrespective of the flow rate of the abrasive particles blasted,these particles impinging onto the surface of the workpiece will have auniform density throughout the entire length of the blast received onthe surface of the workpiece, and that the distance'through which thework surface is processed by the blasted particles is prolonged, andthat this processing requires a much reduced length of time as comparedwith the prior art without causing any uneven result of processing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing apreferred example of the deflector according to the present invention.

FIG. 2 is a side view of the same deflector shown in FIG. 1.

FIG. 3 is a side view showing another preferred example of the deflectorembodying the present invention.

FIG. 4 is a side view showing still another preferred example of thedeflector embodying the present invention.

FIG. 5 is a perspective view in an exploded fashion of the deflectorshown in FIG. 4.

FIGS. 6 through 7 show the structure and function of a knownabrasive-accelerator of a blasting machine, in which:

FIG. 6 is a vertical sectional view of the abrasiveaccelerator; and

FIG. 7 is a sectional view, taken along the line VII- VII in FIG. 6, ofthe deflector, vanes and impeller.

FIG. 8 is a side view of a known deflector used in theabrasive-accelerator shown inFIGS. 6 and 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to satisfythe aforesaid object, the deflector according to the present inventionis provided with a slot having a parallelogram configuration for hurlingabrasive particles therethrough to the vanes. This slot opens throughthe circumferential wall of the deflector with an inclination relativeto the central longitudinal axis of the deflector. Moreover, this slotis such that its width between the opposing two outermost edgespositioned radially of and possibly in parallel with the centrallongitudinal axis of the deflector is determined by the angle of blastof the abrasive particles discharged from the vanes, and that theoverall axial length of the slot is not larger than the breadth W of thevane. Such a slot enables the abrasive particles to be hurled outuniformly along the edges of opening of the slot which is inclinedrelative to the longitudinal central axis of the deflector. At the sametime, the hurled particles of abrasive are restricted of the extensionof their spread by these edges of opening. As a consequence, theabrasive particles are hurled onto the vane in uniform density with alength equal to the axial length of opposing two edges of opening andwith a breadth equal to the breadth of the other opposing two edges ofopening of the inclined parallelogram slot. Because of this arranement,it is possible to blast abrasive particles onto the surface of theworkpiece in uniform density throughout the desired end-to-end distanceof blast, even when the rate of blast of the abrasive particles issubstantially small. Also, because the area of opening of the slotthrough which the particles of abrasive are hurled out is small ascompared with that of the deflector of the prior art, these abrasiveparticles are never discharged in an excessive amount, and this preventsthe aforesaid undesirable phenomenon of interference between thebouncing particles and the fresh particles, thus keeping uneven blastingfrom taking place.

Referring now to the drawings, the examples of the deflector shown inFIGS. 1 through 3 are each constructed to be used in the apparatus shownin FIGS. 6 and 7. At one end of the hollow tubular body is provided,integrally therewith, a plate 17 having an opening 16 for receiving animpeller 7. At the other end of this body 15 is mounted an attachment 18so that the body 15 is detachably attached to a chute 3 by means of thisattachment 18. A slot 12 is formed through the circumferential wall ofthe body 15 for hurling out abrasive particles supplied from the chute3.

In the examples shown in FIGS. 1 and 2, the slot 12 is of aparallelogram configuration and opens through the wall of the body 15with an inclination relative to the longitudinal central axis C of thedeflector or to the central rotary axis of the impeller 7 or the vanes.Each of a pair of parallel edges 12b and 12b of opening of said slot 12is formed in such a way that the length of this edge b corresponds tothe line of arc defined on the circumferential wall of the body 15 witha center angle a of the opening namely, with an angle a which issubstantially equal to the angle B through which the abrasive particlesare blasted from the vane. The other pair of edges 12a and 12a ofopening which are parallel with each other are formed so that thedistance a between these two edges 12a and 12a is of the followingrelation with respect to the breadth W of the vane 6: a 2 W. As aconsequence the length of the edge 12b of the opening has the followingrelation with respect to the breadth W of the vane: a E W.

In the embodiment shown in FIG. 3, the slot 12 is of a parallelogramshape as in the preceding example. This slot opens through thecircumferential wall of the body 15 with an inclination relative to thelongitudinal central axis C of the deflector. However, it will be notedthat the edges 12a and 12a of opening are arranged in a differentfashion as compared with those shown in FIG. 2. More specifically, thesetwo edges 12a and 12a are arranged so as to be parallel with thelongitudinal central axis of the deflector. A deflector having a slot ofsuch a shape may present a slight unevenness in the density of theabrasive particles blasted from the vane, but still the blast issufficiently useful in actual operation. In each of these examples,there is formed only a single slot in the body 15. If necessary,however, for example if it is intended to blast abrasive particles ontotwo separate workpieces, there may be provided another or a second slotformed through the circumferential wall of the body 15 at a positiondiametrically opposite to the first one.

In the deflector shown in FIGS. 4 and 5, the area of opening of the slotis arranged so that it can be varied freely. This body is comprised oftwo body sections, one of which is inserted in the other one of thesetwo body sections. The first one of the two body sections 15A is of ahollow tubular shape and has at one end a flange 18 which is integralwith the body section 15A and which is to be attached to the chute 3.The other or the second body section 153 into which said first bodysection 15A is to be rotatably inserted has also a hollow tubular shapeand is provided at one end with a ring 19 for limiting the unnecessaryaxial movement of the body section 15A and at the other end with a plate17 having an opening 16 for receiving an impeller 16. A slot 12 isarranged to be formed when thecutouts formed through the circumferentialwalls of these two body sections, respectively, are rendered to overlapeach other as the second body section which receives or the first bodysection therein is rotated relative to the first one. Because of thisarrangement, it should be noted that each of the pair of edges 12b and12b of the openings of these two cut-outs is inclined relative to thelongitudinal central axis C of the deflector, whereas the edges 12a and12a of the other pair are perpendicular to said longitudinal centralaxis of the deflector. Moreover, the axial length a between the edges12a and 12a is of the following relation with respect to the breadth Wof the vane: a E W. On the other hand, the length b between the twooutermost ends of the edges 12b and 12b is determined so as to be equalto the line of are formed on the circumferential wall of the body tocorrespond to the angle of blast of the abrasive particles deliveredfrom the vane.

In a deflector described above, it is possible to acquire an area ofopening of the slot which meets the rate of flow of abrasive particles,without changing the conditions in which the abrasive particles arehurled onto the vane. The control of the area of opening of the slot canbe effected, for example, by providing teeth or gear formation on theperiphery of the ring 19 of the body section 15A so that this gear isrotated externally of the accelerator.

I claim:

1. A deflector for an abrasive-accelerator in a blasting machine whichincludes a rotatable impeller, means for conveying abrasive material tosaid impeller and a plurality of vanes for directing said abrasivematerial onto a workpiece, the improvement comprising a hollow tubulardeflector body having one end open for receiving said impeller, saidimpeller being rotatably positioned within said deflector body, saiddeflector body having at least one slot formed through thecircumferential wall thereof for permitting abrasive particles to behurdled out to said vanes of said accelerator through said slot, whereinsaid slot is of a parallelogram shape and forms an opening in said wallof said body with an inclination relative to the longitudinal centralaxis of the deflector and wherein two edges of the slot are arrangedperpendicular to the longitudinal central axis of the deflector.

1. A deflector for an abrasive-accelerator in a blasting machine whichincludes a rotatable impeller, means for conveying abrasive material tosaid impeller and a plurality of vanes for directing said abrasivematerial onto a workpiece, the improvement comprising a hollow tubulardeflector body having one end open for receiving said impeller, saidimpeller being rotatably positioned within said deflector body, saiddeflector body having at least one slot formed through thecircumferential wall thereof for permitting abrasive particles to behurdled out to said vanes of said accelerator through said slot, whereinsaid slot is of a parallelogram shape and forms an opening in said wallof said body with an inclination relative to the longitudinal centralaxis of the deflector and wherein two edges of the slot are arrangedperpendicular to the longitudinal central axis of the deflector.